Metal studs used in modern construction are formed with openings for components, such as electrical cables, electrical conduit, pipes and the like, that extend through the studs. These openings, which are formed in various ways, such as by stamping, cutting, punching and the like, often have sharp edges which can abrade or cut cable insulation or otherwise damage the components extending through the stud openings. Consequently, it is a common practice to protect provide bushings which fit into the stud openings to cover their edges.
Various types of bushings are known and used for the purpose described. One known construction is composed of two parts which snap together when the bushing is installed in a stud opening. This type of bushing has several disadvantages and objections, including the need to make and store multiple parts, and the time and inconvenience of handling and assembling the bushing parts on site.
One piece bushings are known, but also present certain problems and disadvantages. For example, some of the conventional one piece bushings are difficult to insert into the stud opening. This is particularly true when the bushings are configured to resist being dislodged as the electrical cables or other components are pulled through them.
Another objection common to both and multiple piece and one piece bushings of the prior art is that they are not designed so that a single bushing can accommodate a wide range of different metal thicknesses. Since metal studs are made with different thicknesses, it has been necessary to maintain a supply of different size bushings that can be selected and used depending upon the stud structure.